CHICAGO — Focal cryoablation results in better local control of prostate cancer than other standard treatments, Dr. Gary Onik said at the annual meeting of the Radiological Society of North America.
“This is a very aggressive treatment, even though it is focal,” said Dr. Onik, director of surgical imaging, Celebration Health/Florida Hospital in Celebration.
Pathologic literature indicates that up to 25% of prostate cancers are unifocal, and that 80% of cases would be appropriate for lumpectomy, he said.
Dr. Onik has performed focal cryoablation on 96 patients with prostate cancer, and has obtained data on 55 patients with at least 1 year of follow-up (range 1–10 years). Prostate-specific antigen (PSA) tests were obtained every 3 months for 2 years, and every 6 months thereafter. Routine biopsies were obtained in the first 26 patients, and all were negative.
At an average of 3.5 years of follow-up, 52 (94.5%) of the 55 patients had stable PSA levels, and were disease-free according to American Society for Therapeutic Radiology and Oncology criteria. Although four patients had to be re-treated after cancer was found in another area of the prostate, there have been no recurrences in treated areas. The results are noteworthy as 29 of the 55 patients were at medium to high risk for recurrence, he said.
Before the procedure, 51 men were potent. After the lumpectomy, 44 (86%) of those 51 men were potent to their satisfaction. All patients were immediately continent.
Lumpectomy candidates are patients with a unifocal tumor or one large index tumor and another small tumor less than 5 mm in diameter. The procedure would not be advised for those with diffuse disease.
When asked by the audience if there is any volume of tumor that he would not treat, Dr. Onik said the critical point is that the disease should be focal, but added that 1 in 10 of the treatments now are for extracapsular disease in which the whole side of the gland is involved.
The key to prostate cryoablation is accurate identification of cancer stage, grade, and location. Standard transrectal ultrasound biopsy results are not sensitive enough, according to Dr. Onik, who has switched to a new 3D biopsy mapping technique.
A prostate cancer patient is shown before (left) and 2 years after focal therapy. Although half of his gland is gone, he is potent and continent 6 years later without evidence of disease. Photos couresty Dr. Gary Onik
